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CH05_Anderson 7/25/01 8:58 AM Page 144

144 CHAPTER FIVE

Fig. 5.22. A turboprop engine.

Thrust Reversers

When you land in a large jet, you need to decelerate the airplane. As
with a car, brakes can be used. But, as we shall see in Chapter 7,
“Airplane Performance,” the energy that the brakes have to absorb is
astounding. Wouldn’t it be nice if we could just turn the engines
around and have them push the other way to decelerate the airplane?
Certainly when you land in a big jet it seems as if they have done just
that. A jet engine can redirect its thrust with a thrust reverser to
accomplish the equivalent result. Though it may seem like it, this
does not mean that the engine works backward, that is, blowing gas
out the front. What a thrust reverser does is to divert the gas in the
jet exhaust and send it forward, i.e., reversing the direction of the
thrust. This is illustrated with the clamshell-type reverser shown
schematically in Figure 5.23. In this figure, the air from the fan is
rerouted out through the cowling while the nozzle blocks the core air